// json常用编码、解码操作

package ghelp

import (
	"bytes"
	"crypto/hmac"
	"crypto/md5"
	"crypto/sha1"
	"crypto/sha256"
	"encoding/base64"
	"encoding/binary"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"sort"
)

// JsonEncode json编码操作
func JsonEncode(data interface{}) string {
	jsonStr, err := json.Marshal(data)
	if err != nil {
		return ""
	}
	return string(jsonStr)
}

// JsonDecode json解码操作
// 成功返回interface, 失败返回nil
func JsonDecode(jsonStr string) interface{} {
	var v interface{}
	err := json.Unmarshal([]byte(jsonStr), &v)
	if err != nil {
		return nil
	}
	return v
}

// JsonDecodeTo json解码操作
// 失败返回错误，成功返回nil
func JsonDecodeTo(jsonStr string, dst interface{}) error {
	err := json.Unmarshal([]byte(jsonStr), &dst)
	return err
}

// Base64Encode base64编码操作
func Base64Encode(data string) string {
	bData := []byte(data)
	return base64.StdEncoding.EncodeToString(bData)
}

// Base64Decode base64解码操作
func Base64Decode(encodeStr string) string {
	bData, err := base64.StdEncoding.DecodeString(encodeStr)
	if err != nil {
		return ""
	}
	return string(bData)
}

// Md5 生成md5字符串， binary为是否设置原始16 字符二进制格式，默认为false
func Md5(data string, binary ...bool) string {
	h := md5.New()
	_, err := h.Write([]byte(data))
	if err != nil {
		return ""
	}
	d := h.Sum(nil)
	if len(binary) > 0 && binary[0] {
		return string(d)
	} else {
		return hex.EncodeToString(d)
	}
}

// Sha1
func Sha1(data string) string {
	h := sha1.New()
	_, err := h.Write([]byte(data))
	if err != nil {
		return ""
	}
	return hex.EncodeToString(h.Sum(nil))
}

// HmacSha256
func HmacSha256(message string, secret string) string {
	key := []byte(secret)
	h := hmac.New(sha256.New, key)
	h.Write([]byte(message))
	return base64.StdEncoding.EncodeToString(h.Sum(nil))
}

var MbTable = []uint16{
	0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241,
	0xC601, 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440,
	0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, 0xCE81, 0x0E40,
	0x0A00, 0xCAC1, 0xCB81, 0x0B40, 0xC901, 0x09C0, 0x0880, 0xC841,
	0xD801, 0x18C0, 0x1980, 0xD941, 0x1B00, 0xDBC1, 0xDA81, 0x1A40,
	0x1E00, 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41,
	0x1400, 0xD4C1, 0xD581, 0x1540, 0xD701, 0x17C0, 0x1680, 0xD641,
	0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, 0xD1C1, 0xD081, 0x1040,
	0xF001, 0x30C0, 0x3180, 0xF141, 0x3300, 0xF3C1, 0xF281, 0x3240,
	0x3600, 0xF6C1, 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480, 0xF441,
	0x3C00, 0xFCC1, 0xFD81, 0x3D40, 0xFF01, 0x3FC0, 0x3E80, 0xFE41,
	0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900, 0xF9C1, 0xF881, 0x3840,
	0x2800, 0xE8C1, 0xE981, 0x2940, 0xEB01, 0x2BC0, 0x2A80, 0xEA41,
	0xEE01, 0x2EC0, 0x2F80, 0xEF41, 0x2D00, 0xEDC1, 0xEC81, 0x2C40,
	0xE401, 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640,
	0x2200, 0xE2C1, 0xE381, 0x2340, 0xE101, 0x21C0, 0x2080, 0xE041,
	0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281, 0x6240,
	0x6600, 0xA6C1, 0xA781, 0x6740, 0xA501, 0x65C0, 0x6480, 0xA441,
	0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01, 0x6FC0, 0x6E80, 0xAE41,
	0xAA01, 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840,
	0x7800, 0xB8C1, 0xB981, 0x7940, 0xBB01, 0x7BC0, 0x7A80, 0xBA41,
	0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40,
	0xB401, 0x74C0, 0x7580, 0xB541, 0x7700, 0xB7C1, 0xB681, 0x7640,
	0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080, 0xB041,
	0x5000, 0x90C1, 0x9181, 0x5140, 0x9301, 0x53C0, 0x5280, 0x9241,
	0x9601, 0x56C0, 0x5780, 0x9741, 0x5500, 0x95C1, 0x9481, 0x5440,
	0x9C01, 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40,
	0x5A00, 0x9AC1, 0x9B81, 0x5B40, 0x9901, 0x59C0, 0x5880, 0x9841,
	0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, 0x8A81, 0x4A40,
	0x4E00, 0x8EC1, 0x8F81, 0x4F40, 0x8D01, 0x4DC0, 0x4C80, 0x8C41,
	0x4400, 0x84C1, 0x8581, 0x4540, 0x8701, 0x47C0, 0x4680, 0x8641,
	0x8201, 0x42C0, 0x4380, 0x8341, 0x4100, 0x81C1, 0x8081, 0x4040}

// Crc16 计算crc modbus
func Crc16(data []byte) []byte {
	var crc16 uint16
	crc16 = 0xffff
	for _, v := range data {
		n := uint8(uint16(v) ^ crc16)
		crc16 >>= 8
		crc16 ^= MbTable[n]
	}
	int16buf := new(bytes.Buffer)
	binary.Write(int16buf, binary.LittleEndian, crc16)
	return int16buf.Bytes()
}

// CheckSum 计算累计校验码
func CheckSum(data []byte) byte {
	var sum byte
	for _, v := range data {
		sum += v
	}
	return sum
}

/*
GenerateSign 生成签名
参数示例如下：
param

	{
	  "corp_id": "ding3590d5bb2ae3356d",
	  "corp_name": "杭州嘉策科技",
	  "corp_logo_url": "",
	  "industry": "信息技术",
	  "auth_info": "",
	  "platform": 1,
	  "status": 1
	}（请求参数内容）

timestamp：1687662061（当前时间戳，精确到秒）
key：ding3590d5bb2ae3356d（平台提供key）
secret：12345678（平台提供密钥，不可泄露）

签名规则、步骤如下
1、将param按map键名升序排好，并如下方式拼接参数
auth_info=&corp_id=ding3590d5bb2ae3356d&corp_logo_url=&corp_name=杭州嘉策科技&industry=信息技术&platform=1&status=1
2、再在字符串尾部拼接上timestamp，key， secret，生成如下字符串
auth_info=&corp_id=ding3590d5bb2ae3356d&corp_logo_url=&corp_name=杭州嘉策科技&industry=信息技术&platform=1&status=1&timestamp=1687662061&key=ding3590d5bb2ae3356d&secret=12345678
3、最后将签名字符串进行md5运行，得到如下签名内容

	da285ec709f8086009672a1b97310988
*/
func GenerateSign(param MAP, timestamp int64, key string, secret string) string {
	// 将请求参数的key提取出来，并排好序
	newKeys := make([]string, 0)
	for k, _ := range param {
		newKeys = append(newKeys, k)
	}
	sort.Strings(newKeys)
	var originStr string
	// 将输入进行标准化的处理
	for _, v := range newKeys {
		originStr += fmt.Sprintf("%v=%v&", v, param[v])
	}
	// 把其他参数拼到验签字符串中
	originStr += fmt.Sprintf("timestamp=%d", timestamp)
	originStr += fmt.Sprintf("key=%s", key)
	originStr += fmt.Sprintf("secret=%s", secret)
	// 使用md5算法进行处理
	sign := Md5(originStr)
	return sign
}
